High flow, hydrogenated styrene-butadiene-styrene block copolymers and applications

Abstract

The invention relates to unique applications for the novel high melt flow, low viscosity, selectively hydrogenated styrene-butadiene-styrene (hSBS) or selectively hydrogenated controlled distribution styrene-butadiene/styrene-styrene (hSBSS) block copolymers, wherein the melt flow rate of said block copolymer is at least 100 g/10 min at 230° C. under 2.16 kg mass according to ASTM D1238. These block copolymers are novel and have the highest melt flow rate of any styrenic block copolymer also possessing high strength and elasticity. It has applications that prior to the present invention were not normally possible due to the normal low melt flow rate of styrenic block copolymers. The present invention also encompasses various fields of use such as a fiberglass hSBS or hSBSS reinforced mat, low viscosity hSBS or hSBSS coatings for industrial uses, hot melt adhesives prepared from hSBS or hSBSS blended with polyalpha-olefins, and elastic film, fiber, and nonwoven constructions using hSBS or hSBSS.

What is claimed is: 
     
       1. A non-pressure sensitive adhesive composition intended for use as a personal hygiene construction adhesive, elastic attachment adhesive, and hot-melt adhesive comprising: a blend of poly-alpha-olefin, styrenic block copolymer, and tackifying resin, said styrenic block copolymer having a melt flow rate greater than about 125 g/10 min at 230° C., and 2.16 kg mass, said styrenic block copolymer being selectively hydrogenated styrene-diene-styrene or selectively hydrogenated controlled distribution styrene-diene/styrene-styrene, where the diene is butadiene, isoprene, or mixtures thereof. 
     
     
       2. The adhesive composition of  claim 1 , wherein said poly-alpha-olefin is present from about 30 to about 80 wt. % of said composition, said styrenic block copolymer is present from about 10 to about 35 wt. % of said composition, and said tackifying resin is present from about 20 to about 60 wt. % of said composition. 
     
     
       3. The adhesive composition of  claim 1 , wherein said poly-alpha-olefin is amorphous. 
     
     
       4. The adhesion composition of  claim 1 , wherein said styrenic block copolymer is a selectively hydrogenated linear or coupled block copolymer having the structure of SDS or (SD) n X, respectively, wherein S is styrene, D is diene or diene/styrene, where n =2 or 3; and X is a coupling agent residue. 
     
     
       5. The adhesive composition of  claim 4 , wherein said styrenic block copolymer has a minimum peak molecular weight of about 45,000; a PSC of between about 18 to about 33%, a vinyl content of about 65 to 80%, a coupling efficiency of about 60 to about 97%, and said diene is hydrogenated at least 90%. 
     
     
       6. The adhesive composition of  claim 1 , wherein said tackifier is compatible with polystyrene. 
     
     
       7. The adhesive composition of  claim 1 , wherein said tackifier is compatible with polybutadiene.